Clutch mechanism



March 2, 1937.

R. P. LEWIS CLUTGH MECHANISM Filed Jan. 10, 1934 2 She ets'-Sheet l m wM m w g/qmw T n l I, A k @w 0 i 0 i u Z aw March 2, 1937. R. P. LEWIS ICLU TCH MECHANISM 2 Sheets-Sheet 2 Filed Jan. 10 1934 1 I. 7. 1 I; i y"777 V a V 4; :r 9 WW m y w 1 Am... mfluw l w ull.

Patented 2, 1 937 2,072,115 onn'ron MECSM Ruben-t l". Lewis, Toledo,Ohio, assignor to Spicer Manufacturing Corporation, Toledo, (Phio, acorporation of Virginia Application January 10, 1934, Serial No. 706,109

2d (llaims.

'tween 2. driving shaft and a driven shaft when the driving shaftattains a predetermined or engaging speed. Mechanisms of this characterhave proven to be highly successful in practice in automotive or likedrives as they have been found to smoothly establish a drive between theprime mover and the load when'the prime mover is accelerated through apredetermined speed range. Clutches of this character have also beenfound in practice to-have a useful life substantially greater than thatof comparable manually operable clutches, despite the fact that theytransmit power through a slipping drive during a large portion of theirnormal operation.

In certain commonly used automotive drives, through the nature of thetransmission or freewheeling or other driven units, universal joints andthe like are employed therein, excessive lostmotion or back-lash existsbetween the driven clutch shaft and the vehicle wheels, with the resultthat if the engine or other prime mover is suddenly coupled to thedriven clutch shaft the last motion or back-lash is almost instanta=neously taken up and an objectionable noise commonly termed a clunkoccurs, causing transmission of a sudden driving impulse or shock to thevehicle wheels.

motion presentin the drive line, the degree of suddenness of clutchengagement, and the magnitude of tlie torque which is initiallytransmitted by the clutch.

It has been found that this shock and the clunk incident thereto can, bereduced to some extent when using a manually operable clutch in thedrive, by allowing the clutch to engage extremely slowly, so as to applya very light initial torque to take up the lost motion The magnitude ofi the clunk is influenced by the amount of lost establish the requisitedrag for proper operation.

(fill. 192-405) before substantial "driving torque is imposed upon thedrive line by full clutch engagement. In practice, however, the averagecar driver is not sufiiciently skilled to operate a manual clutchsatisfactorily in this way. It hasalso been found that where automaticor speed responsive clutches are incorporated in such drives embody-.lng substantial lost motion, particularly when the clutch clearancesare not properly adjusted, it is only by exercising care to depress theac- 10 celerator'slowly in its initial movement that the I clutch can beoperated to take up the back lash in the drive and to pick up the loadwithout proture just described, by adjusting the parts so that when theengine is operating at idling speed, the frictionalplates or shoes aredisposed in a very light engagement, with'the result that a slight dragis present which tends tov take up the lost motion or back-lash in thedrive line. This remedy, while simple and effective, has been found tobe impractical, since if the adjustment is carelessly made, so that thetorque transmitted from the driving .to the driven shaft, as' the resultof the drag, is too great, the driving and driven shafts will tend torotate in unison with the result that excessive facing wear may becaused. When the facings undergo only minute dimensional changes as aresult of wear during normal operation, the clutch no longer drags, withthe result that the back-lash absorption is lost and the clutch must bere-adjusted to re- With a too'close adjustment the facings may alsoexpand due to heating in operation, thereby preventing the automaticfunctioning of the clutch due to imposition of too great a drag topermit proper release of the clutch when the 2 engine is idling so thatgears can be shifted and the vehicle will come to rest without a manualdeclutching operation.

The present invention aims to eliminate the above mentionedobjectionable operating characteristics of manual and automatic clutchesand to provide novel mechanisms that will take up lost motion in a driveline without shock and without resorting to any of the expedients thathave been heretofore proposed.

It is accordingly a primary object of the present invention to devise anovel power transmitting mechanism which is particularly adapted for useand to eliminate shock in drive lines having substantial back-lash,although it is not limited in use to such drives.

It is a further major object of my invention to devise, for use inclutches of the character which are adapted to engage and establish apower transmitting connection between driving and driven shafts, novelmeans for causing the driving shaft to impress a torque of smallmagnitude upon the driven shaft prior to engagement of the clutch undercertain predetermined operating conditions.

A further important object of my invention resides in the provision ofautomatic clutches of the character that are adapted to establish apower transmitting connection between driving and driven shafts when oneof the shafts attains a predetermined speed, with means forautomatically causing a torque of low magnitude to be transmittedbetween the shafts prior to engagement of the clutch when the drivingshaft is suddenly accelerated.

My invention further provides an automatic clutch mechanism particularlyadapted for use in drives having excessive back-lash, which willautomatically establish a power transmitting connection between drivingand driven parts of the drive when certain parts attain a predeterminedspeed, and yet that will not take the back-lash up so suddenly as to.produce an objectionable shock in the drive, no matter how suddenly theparts are accelerated.

Another object of my invention is to devise a clutch mechanism whichwill automatically establish a low-torque drive between driving anddriven shafts when one of the shafts is given apredeterminedacceleration, and which is operable to establish a high-torqueconnection between the shafts when one of the shafts attains apredetermined speed.

It isa further object of the invention to devise, for use in anautomatic clutch of the type which is operable to establish a drivebetween driving and driven shafts when one of the shafts atains apredetermined speed, and which is associated with adrive havingsubstantial back-lash therein, means for automatically and quietlytaking up the back-lash in the drive should the shafts be given anacceleration of such magnitude as to otherwise cause the clutch tosuddenly take up the back-lash with an objectionable shock.

Another object of my'invention is to provide clutch mechanisms having anacceleration responsive means with and without speed respon sive meansfor establishing a power transmitting connection between driving anddriven parts.

A further object of my invention is to provide friction clutches of thetype adaptedto establish a power-transmitting connection between drivingand driven members, with means that will transmit a torque of smallmagnitufd between the members when the driving member is accelerao'iarieated, and which will transmit a torque of greater magnitude between themembers if the driving member tends to overrun with respect to thedriven member when it is accelerated.

It is a further object of my invention to devise, for use in frictionclutches, an acceleration responsive device for transmitting torque thatis so designed as to manifest a self-energizing tendency when it istransmitting torque in one direction, and whichv will manifest aself-de-energizing tendency when it tends to transmit torque in theopposite direction. 1

It is a still further object of this invention to devise a mechanism forautomatically transmitting torque between driving .and driven shaftswhen one of the shafts is given a predetermined acceleration, and whichmay be rendered incapable of transmitting torque when the member is soaccelerated.

A further object of the invention resides in devising a clutch having apower transmitting element that is adapted to be acted upon by anacceleration responsive mechanism and a speedresponslve mechanism, fortransmitting torque of low and high magnitude respectively.

Another object of my invention resides in the provision of automaticclutches of the type that are adapted to establish a power transmittingdrive between driving and driven members when one of the members attainsa predetermined speed, with means for automatically causing a torque oflow magnitude to be transmitted between the members when one of themembers is suddenly accelerated or decelerated.

A further object of my invention is to devise an automatic clutchmechanism particularly adapted for use in drives having excessiveback-lash, which will automatically establish a power transmittingconnection between driving and driven parts of the drive when certainparts attain a predeter mined speed, and yet that will not take up theback-lash so suddenly as to produce an objectionable shock in the drive,no matter how suddenly the parts are accelerated or decelerated.

It is another object of my invention to provide friction clutches of thetype adapted to establish a power transmitting connection betweendriving and. driven members, with means that will transmit a torque ofsmall magnitude between the members when the driving member isaccelerated or decelerated, and which will transmit a torque of greatermagnitude between the members if the driving member tends to resist theaccelerating or decelerating forces imparted to it by the drivingfriction plate clutch device that will automatically establish adrivingconnection between driving and driven members when anacceleration of predetermined magnitude is'imparted to one of them.

Another object of my invention is to devise, for-use in clutches of thecharacter having members mounted for engagement and disengagement; meansfor transmitting torque between the members when they are disengaged andone of them is given predetermined acceleration.-

and which is inoperative to so transmit torque under certain rotativeconditions of the members.

Another object is to provide a clutch mechanism of the type having africtional pressure plate, with an auxiliary pressure plate' which ismovablymounted with respect thereto, and is operable to transmit torqueindependently of,

and concurrently with the pressure plate.

It is another object to devise a novel pressure plate for frictionclutches, having an auxiliary power transmitting means adaptedtotransmit power independently of the pressure plate at times, and atother times transmit power as a part of the pressure plate.

Other objects of my invention will appear as I the detailed descriptionthereof proceeds in connection with the annexed drawings, and from theappended claims. i

10 In the drawings,

Figure 1 is a longitudinal sectional view illustrating my invention asbeing embodied in an automatic, or speed responsive clutch.

Figure 2 is a view taken substantially on the la line IIII of-Figure 1,with parts broken away to more clearly illustrate the structureinvolved.

Figure 3 is a fragmental sectional view of the clutch shown in Figure 1and illustrates one of the hold-back and driving spring assembliesutilized 0 therein.

Figure 7 is a view similar to Figure 4, but it illustrates the relationof the parts when the clutch is undergoing either manual or automaticdisengagement, with the driven shaft tending to overrun the drivingshaft.

- Figure 8 is a fragmental sectional view illustrating my inventionincorporated in a double plate automatic clutch. Y

Figure 9 is a view similar to Figure 8 but illustrates a manuallyoperable clutch equipped 40 with my invention.

Figure 10 is a fragmental sectional view of a clutch having a modifiedform of my invention applied thereto, and

Figure 11 is a detailed sectional view taken on 45 the line m xr ofFigure 10.

Figure 12 is a fragmental sectional view similar to Figure 11, butillustrating a further modification of my invention.

Figure 13 is a fragmental sectional view il- 0 lustrating another formof my invention.

With continued reference to the drawings.

wherein like reference characters designate like parts throughout theseveral views thereof, and with particular reference to Figures 1 to '7,in-

55 elusive, I have illustrated my invention as being incorporated in anautomatic clutch, having a driving shaft l and a driven shaft 2, whichare .mounted for relative rotation.

Secured to a flange provided on driving shaft 0 l, by means of boltassemblies 3 or the like, is

a flywheel 4. Secured to flywheel 4, by means of cap screws 5 is'a coveror housing member 8. A pressure plate 1, which will be hereinaftertermed the automatic plate, is disposed within 55 cover 8 and is mountedfor synchronous rotation therewith by means of driving lugs 8 which arewelded or otherwise suitably secured to cove-r 6 and extend intorecesses 9 located in plate -I.

A driven member, designated generally at H 70 and having facings l2secured thereto in any well knownmanner, is splined to shaft 2 and isadapted to be frictionally gripped between plate I and the flywheelface. A reaction plate or member I3 is disposed adjacent plate 1 and the75 two are urged toward each other by means of holdback springs it whichact against plate 13 and bear against the head ofcap screw members l5,which extend through apertures in plate l3 and are threaded. into plateI. Plates 1 and I3 are normally urged toward the flywheel by means of aplurality of compression springs I6, which act against plate It andcover 6.

The automatic and reaction plate assembly is adapted to be moved awayfrom the flywheel against the action of springs It by means of aplurality of levers i! which are pivotally supported on brackets 58carried by cover 6, and their outer ends are adapted to cooperate withnut and washer assemblies 89 which are carried by bolts 20. Bolts arefrictionally fitted into apertures in plate i3 and are encircled byanti-rattle assemblies 2| which tend to maintain lever l! in contactwith nut and washer assemblies l9 at all times.

The inner ends of lever ill cooperate with a throwout assemblydesignated generally as 22 which is mounted for axial movement on asupport 23 which is secured to clutch housing 24 in any well knownmanner (not shown). Axial movement of throwout assembly 22 is eilectedby means of a fork 25, which is secured to-a throwout shaft 26.

Plate 7 is actuated by means of a plurality of centrifugally operableweight members designated generally at 2'1, which have lever portionsextending through apertures in plate l3, and carry ofiset portions 28which are normally clamped between plate I3 and the bottom of recesseslocated in plate 5 by springs M as seen in Figure 1 when the prime moverassociated with the driving shaft is operating at or below idling speed.Weights 21 are adapted to rock outwardly about fulcrums 28 provided onportions 23 to thereby force plates 7 and I3 away from each otheragainst the action of springs l4, and their operation will be amplifiedas the specification proceeds. I

The clutch just described is more fully disclosed in copendingapplication S. N. 676,567,

filed June 19, 1933, and as its structural details When the engine isaccelerated with shaft 26 disposed in the position just described,weights 2? rock outwardly about their fulcrums and bring the plates intoengagement, and as the clutch action is automatic, or speed responsiveunder these conditions, this position of shaft 26 will be termed itsautomatic position.

Shaft 25 may be rocked in a counter clockwise direction from theposition shown in Figure 1 into disengaging position. Rocking movementof shaft 26 in this manner, through levers l1, and bolts 20, causesreaction plate 13' to move to the right against the action of springsl6, and by reason of the connection established by the holdbackassemblies, such movement of plate l3 disposes plate I in such aposition that speed responsive actuation of weights 2! is ineffective tobring it into engagement with the driven member. v

Shaft 26 may be allowed to rock to the other side of automatic positionin a' clockwise direction to allow springs it to force plate I into en-For instance, it may be releasably held in automatic position againstthe action of springs is, by means of a latch mechanism of the characterdisclosed in copending application 688,018, flied September 2nd, 1933,or it may be controlled so as to introduce a power responsive phase intoclutch operation by means of devices of the gemeral character disclosedin copending application S. N. 669,766, filed May 6th, 1933, if desired.For the purposes of the present application shaft 26 may be consideredas extending outwardly of housing 24 and carrying a clutch pedal thereon(not shown).

I preferably provide the clutch just described with means for imposing atorque of low magnitude upon shaft 2 when shaft I is suddenlyaccelerated, for the purpose of softly taking up any back-lash that maybe present in the units driven by the clutch, and although it may takethe form of any suitable mechanism and be directly associated withshafts! or 2, in the present embodiment of my invention it preferablytakes the form of an auxiliary plate, which is adapted to transmit powerfrom plate 1 to the driven member.

With particular reference to Figures 1, 2, and

.4 of the drawings, plate I is provided with an annular groovedesignated generally at 3!, which provides a cylindrical wall 32 and aflat face or seat 33. An auxiliary plate or ring 34, having a mass whichis predetermined by the factors entering into the desired operatingcharacteristics of the particular clutch, is disposed in groove 3| andis adapted to be journaled in wall 32 thereof. The adjacent frictionalsurfaces of plates 34 and 1 are preferably chamfered to avoid scoring offacing i2,-an l plate 34 is preferably so dimensioned, that when it isin firm contact with seat or face 33, its frictional surface will lie insubstantially the same plane as the frictional surface of plate 1, sothat plates 1 and 34 may, under such conditions, function as a unitarypressure plate.

Plate 34 may be actuated toward and away from the flywheel, in responseto acceleration of shaft l, by any suitable means, but in the presentinstance it takes the form of preferably three pins 35, which arefrictionally fitted into recesses 33, located at preferably 120intervals in plate 34. Pins 35 are received in grooves 31 formed inplate 1, and with reference to Figure 4 of the drawings, grooves 31 arepreferably disposed at an angle of 30 with respect to the driving faceof' plate 1, although it is to be understood that this angle may bevaried as desired, depending upon the mass or rotational inertia ofplate 34, and the desired operating characteristics of the particularclutch involved.

Pins 35 are adapted to cooperate in driving en- 'gagement with walls orfaces 38 and 39 of recesses 31. Walls.38 are adapted to engage pins 35and produce disengaging or retracting movement of plate 34, and walls 39are'adapted to engage pins 35 and produce engaging or advancing movementof plate 34 in a manner that will be pointed out in more detail as thespecification proceeds. With -the parts rotating in the directionsindicated by the arrows in Figures 1, 2, and 4, when shaft I is given anacceleration of predetermined magnitude, plate 34, by virtue'of itsinertia, tends to remain stationary with respect to plate 1, withacvarre the result that pins 35 thereof are forced into engagement withwalls 33, and tend to advance or-move plate 34 toward the flywheel andinto the position illustrated in Figure 5. Conversely, whenshaft l andplate 1 are suddenly decelerated, the angular or rotational momentum ofplate 34 opposes the decelerating action, and pins 35 of plate 34cooperate with walls 38 and tend to retract plate 34 and move it intothe position illustrated in Figure 4. In this connection it should beunderstood that although I have disclosed an auxiliary plate that isadapted to undergo advancing movement when the driving shaft isaccelerated, and is adapted to undergo retracting movement when thedriving shaft is decelerated, it is to be understood, that if desired,walls 38 of slots 31 may be designed so as to lie parallel with the axisof the mechanism and the springs or other means relied upon to retractplate 34. Moreover, walls 38 may be oppositely inclined if desired, soas to cause plate 34 to undergo advancing or engaging movement both whenthe driving shaft is accelerated or decelerated, and the appended claimsare intended to embrace an organization of this character.

In the present embodiment of my invention, I preferably so design andrelate pins 35 and grooves 31, that the driving face of plate 34 willremain normal to the axis of the mechanism when it is undergoingadvancing and retracting movement, but it is to be understood that ifother than a normal plate action is desired in the particu lar clutchinvolved, the structure may be suitably modified, and the appendedclaims are intended to embrace my invention when the parts are relatedin this manner.

Operation to the driven assembly, which picks up any backlash therein,and when the parts attain a predetermined speed the automatic platepicks up the driven member. The automatic engaging operation, as itoccurs when the driving shaft is only moderately accelerated, will nowbe described.

As shaft l and flywheel 4 are accelerated to a speed slightly in excessof idling speed, the parts remain in the disengaged position illustratedin Figure 1' by reason of the action of holdback springs i4 which actupon portions 23 of weights 1 and thereby maintain them in their inneror neutral position. When shaft l attains a higher speed, which ispredetermined by the mass. of

weights 21 and the strength of springs l4, weights 21 rock outwardlyabout their fulcrums in response to centrifugal force. As this occurs,portions 28 of weights 21 act against plate I and After the drivenmember is thus frictionally' gripped or'clamped between automatic plate1, auxiliary plate 34 and the flywheel, movement awaits of plates 1 and34 is substantially, arrested and further rocking movement of weights21, in response to further increasing centrifugal force, causes reactionplate l3 to beforced away from the flywheel against the action ofspring, l6. Movement of plate l3 in this manner causes pressure toslowly build upin springs I6 and a corresponding pressure is built upbetween plates i and 34 and the driven member.

A power transmitting connection is thereby automatically establishedbetween shafts I and 2, and the magnitude of the torque transmittedtherebetween, upon initial engagement of plates 3 and 34 with the drivenmember, is of such low magnitude that any backlash that may be presentin the driven assembly connected to shaft 2, such as a transmission orfree wheeling unit, is

I quietly and softly taken up, with the result that when weights 21 rockoutwardly, and cause substantial torque to be transmitted from shaft lto shaft 2, there is no slack in the drive line.

When shaft i attains a predetermined speed during the acceleratingoperation just described,

weights 2! rock further outwardly and build up to cause further pressureto be built up between the plates. The plates are thereby held indriving engagement under a predetermined pressure, and a positivefriction coupling exists between shafts i and 2.

On the other hand should shaft i be given a sudden acceleration, theengaging operation resulting therefrom occurs in the following manner.With the parts disposed in the position illustrated in Figures 1 and 4,and with automatic plate 1 rotating in the direction indicated in thisfigure, acceleration of plate 1, through slots 31 and pins 35, tends toaccelerate plate 34 or increase the rotational momentum thereof. Plate34, by reason of its inertia, tends to resist acceleration, and themagnitude of the forces set up therein and transmitted from pins 35 toplate 7, depend upon the rotational inertia of plate 34 and themagnitude of the acceleration imparted to plate 1. In the presentinstance the inertia forces set up in plate 34 are indicated in Figure 4as F1, and their components, which are applied to walls 39 of slots 31are indicated at R1. Application of these forces to inclined walls 39causes plate 34 to move toward the flywheel into engagement with thedriven member and the parts then assume the position illustrated inFigure 5.

When plate 34 is brought into engagement with the driven member in themanner just described, and with shaft 2 rotating at a speed lower thanthat of shaft I, a drag is immediately imto augment forces R1, andincrease the pressure of engagement of plate 34 with the driven member,with the result that plate 34 undergoes a self-energizing action. ForcesR: and R1 are of low magnitude, but they are sumcient to force plate 34into engagement with the driven memher under a pressure that issufficient to take up any back-lash in the driven assembly associatedwith shaft 2, and as this action preferably takes place before plate lis actuated, it is apparent that it is impossible to produce a clurik,no matter how suddenly shaft 1 is accelerated.

Acceleration of shaft 1 accordingly automatically establishes a light,or non-power transmitting connection between it and shaft 2, with theresult that no matter how much play or backlash may be present in theunits that are driven by shaft 2, it is smoothly taken up, so that whenplate 5 is actuated and substantial power is transmitted from shaft l toshaft 2 no clunk or shock will occur. When the driven member is grippedbetween the auxiliary plate 34 and the flywheel in the manner justdescribed, and shaft 8 attains a speed corresponding to the operatingspeed of weights 2?, they rock outwardly and force plate 1 intoengagement with the driven member against the action of spring H4 in themanner previously described. .When this operation takes place, auxiliaryplate 34 remains in engagement with the driven member and pins 35 actagainst the walls 33 of groove 31 and when the operation iscompleted theparts assume the position illustrated in Figure 6, with plate 34disposed in engagement with its seat 33 formed on plate 7. Plate 34 isaccordingly picked up by the automatic plate, and further outwardmovement of weights 2'! causes pressure to build up between plates 34and the'driven member at a rate proportional to that pressure built upbetween plate I and the driven member.

With the. clutch mechanism just described installed ln a conventionalmotor vehicle, and with the transmission in gear, and the clutch fullyengaged in the manner just described, through either a moderate orsudden acceleration of shaft I, and it is desired to stop the vehicle,the accelerator is released and the brakes are applied. when thevehicle, under the combined braking influence of the engine and thebrake mechanism is decelerated to a predetermined speed, springs l4overcome the centrifugal forces developed in weights 2'! and force theminwardly to the position shown in Figure 1, and disengage plate i fromthe driven member. celerator is released under these conditions, theengine tends to drop to idling speed, with the result that shaft Z'tendsto overrun with re pect to shaft 8. ll'he relation of the parts, sutantially at the instant of disengagement of automatic plate I from thedrlven member, is illustrated in Figure 7, and the overrunnlng actionjust described sets up forces indicated at F3 in plate 34 whosecomponents, indicated as B5, are

transmitted from' pins 35 to walls 38 of groove 31, with the result thatplate 34 moves away from the flywheel and out of engagement with thesired, the accelerator may be depressed to pro- .duce acceleration ofshaft I and automatic reengagement of the clutch in the mannerpreviously described. Although the auxiliary plate tends to undergo aself-de-energizing or retracting fmovement whenever shaft 2 tends toover- 'run with respect to shaft I, this action is only efiective toactually disengage plate 34 from the driven member when automatic plate"I has become disengaged from the driven member in 0 the manner justdescribed. Accordingly, when the accelerator is released and the clutchis fully engaged, the action. of the centrifugal weights maintains plate34 in contact with its seat 33, irrespective of any self-de-energizingor retractmg forces that may be set up therein.

As has been previously explained, shaft 26 may be rocked in acounterclockwise direction to disengage the clutch, and in a motorvehicle it is frequently desirable when the free wheeling unit islockedout, to disengage the clutch in this manner for the purpose ofshifting the transmission gears, l I

With the clutch fully engaged in the manner previously described, withweights 2'! in their outer positions, if the accelerator is released,the clutch remains engaged until the driving and driven shaftsdecelerate to a speedwhere holdback springs I4 overcome the centrifugalforces set up in weights 21, and at this time springs I4 disengage theplates and rock weights 2! into their inner position. Assuming that thetrans mission is in gear and the accelerator is released when thisoperation is effected, driven member II continues to rotate as it isdriven by the momentum of the vehicle transmitted through the finaldrive, the transmission and shaft 2,

under the conditions just described, the backlash in the drive line is"taken .up, with the respect to' fiow of power from the load to theengine, but if the engine is accelerated to again drive the load, theback-lash in the drive line must be again taken up in the mannerpreviously described.

When the engine is accelerated, after the clutch has been disengaged inthe manner just described, and the veln'cle is coastingyauxiliary plate34 silently'takes up the back-lash in the rotating drive line parts; andthe automatic.

plate is then actuated to'pick up the vehicle in the manner previouslyset forth. The auxiliary plate is accordingly operable to take up thedrive line back-lash whenever the driving shaft is accelerated,regardless of whether the driven shaft is rotating or stationary at thetime. If the clutch is installed in a vehicle having freewheeling, itautomatically disengages whenever the accelerator is released, as theengine ma y drop to idling speed, and when the engine is.

again accelerated to pick up the vehicle the am:- illary plate functionsin the manner just described to silently take up the back-lash in thedrive line. The auxiliary plate also functions in this manner when theengine is accelerated to pick upthe moving vehicle after the clutch hasbeen manually disengaged in the manner that will now be described.

With the clutch fully engaged in the manner previously described,counterclockwise rocking movement of shaft 26 moves plate l3, and plate'I,.connected thereto by the holdback assemblies,

to the right with the result that plate 1 is disengaged from the drivenmember. Assuming that the accelerator is released, driven shaft 2 tendsto overrim driving shaft I, and as soon as plate 1 'I has beendisengaged from the driven meniber.

de-energizing forces Ra (Figure 7) applied by pins 35 to walls 38 ofslots 31, promptly disengage auxiliary plate 34 from the driven memberwith the result that depression of the clutch pedal insures cleandisengagement of the clutch.

H the magnitude of the deceleration of shaft 9, during the disengagingoperation just described 'is sufliciently high, the angular momentum ofplate 34, causes it to tend to resist the deceleration applied theretoby plate I, and the forces set up therein are indicated in Figure 7 asF4. The active components of forces F4 are indicated as R4, and they areapplied to walls 38 of grooves 31, and as they augment forces R3 theyassist in disengaging plate 34 from the driven member.

After the declutching operation just described has been effected, thevehicle transmission may be readily shifted from a lower to a highergear and the clutch pedal released to re-engage the plates.

If it is desired to shift the transmission from a higher to a lowergear, shaft 26 is rocked to disengage the clutch in the manner justdescribed, and when the transmission .has been placed in neutral, theaccelerator is suddenly depressed, whichresults in driving shaft Iundergoing a certain acceleration. The accelerationimparted to shaft Icauses plate 34 to be engaged with the driven member in the mannerpreviously described, with the result that shaft 2 and the transmissioncounter shaft are accelerated. The transmission may then be shifted intothe lower selected gear quite readilytvithout clashing in view of thefact that the accelerating operation has substantially synchronized thetransmission It is apparent that the provision of clutches with my novelauxiliary. plate organization not only eliminates any possibility ofobjectionable the clutch disengagement is clean, with the result.

that the transmission parts ,may promptly decelerate and synchronize.

If it is desired to establish a driving connection between shafts I and{when shaft I is rotating below the operating speed of weights 21, shaft26 may be rocked clockwise in the manner previously described, so as toallow springs I6 to force automatic plate 1 towards the flywheel andgripthe driven member. When plate I undergoes movement in this manner, seat33 formed thereon picks up auxiliary plate 34 andcauses it to belikewise brought into engagement with the 'driven member. Spring I6accordingly causes the driven member to be frictionally gripped byplates I and 34, and a driving connection is thereby established betweenshafts I and 2.

Although I have disclosed a particular form of mechanism forautomatically advancing the auxiliary plate, and I prefer to use thisstructure by reason of its simplicity, it is to be understood that anyother suitable mechanism may be employed for producing this resultwithout departing from the spirit of my invention. For instance, theouter present mechanism advances the auxiliary plate when the drivingshaft is accelerated, and retracts it when the engine is decelerated,the pin and groove arrangement may be so designed as to effect advancingmovement of the auxiliary plate upon deceleration as well asacceleration of the driving shaft if desired.

Movement of the auxiliary plate toward retracted position is definitelylimited by cooperating seat 33 provided on plate I, and although it isnot deemed necessary to provide a stop for limiting advancing movementof the auxiliary plate, it is to be understood that such stop may beemployed without departing from the spirit of the present invention.

Referring now to Figure 8 of the drawings, I have illustrated myinvention as being applied to an automatic clutch of the double platetype, and its operation is substantially similar to that of theautomatic clutch just described.

With continued reference to Figure 8, cover 6 is secured to anintegrally formed rim portion 45 formed on flywheel 4a. An intermediateplate 46, having driving lugs 41 provided thereon, is disposed betweendriven member H and a similar driven member I la. Driving lugs 41 aredisposed in recesses 48 formed in rim 45 and are provided with bossportions 49 which are adapted to engage cover 6 for a purpose that willpresently appear. A plurality of compression springs 55, associated withretaining bushings 52, are located in lugs 41 and bear against the faceof the fly-= wheel. When shaft 26 is disposed in automatic position, theparts appear as seen in Figure 8, with the plates disengaged and withsprings 5i holding plate 48 with its boss portions 49 in contact withcover 6. The remaining parts of the mechanism are identical in structureand function to those employed in the device illustrated in Figures 1 to'7, inclusive, and therefore similar reference characters have beenemployed to designate them, and they will not be further described.

In this form of my invention, weights 2i rock outwardly and grip thedriven member between plates l and 46 in the manner previously describedin connection with the first modification of my invention upon moderateac= celeration of shaft i. Further rocking movement of plate 7 causesplate 46 to move away from cover 6 and toward the flywheel against theaction of springs 5i and causes it to grip driven member Ha, between itand the flywheel. When driven members it and Na. have been grippedbetween their respective plates, further outward rocking movement ofplate 2'! causes pressure tobebuilt up in springs H6 in the mannerdescribed in connection with the first form of my invention.

In the event that the shaft 26 is disposed in automatic position, andshaftl is suddenly accelerated, auxiliary plate 34 advances in themanner described in connection with the first form of my invention andgrips driven member ll between it and plate 46, thereby taking up anyback-lash in the driven line. In this form of the invention, it ispreferable that the engaging forces exerted upon plate 34 are of suchmagnitude that when it is actuated it does not causeplate 46 to movetoward the flywheel against the action of springs 5|, and clamp thesecond driven member between it and the flywheel, although. if desired,these parts may be designed to produce thisresult.

'However, it has been found .to be perfectly satisfactory in practicefor the auxiliary plate to merely pick up one driven member in order totake the back-lash out of the driven line. It is to be understood,however, that in some installations if desired, a second auxiliary platemay be associated with plate 46 or the flywheel and designed to engagedriven member iia. and the appended claims are intended to covermechanisms of this character. Y

In Figure 9 I have shown the clutch illustrated in Figure l as beingdesigned so as to operate as a manual clutch. In this form of theinvention bolts 20a are provided with a reduced portion which isthreaded into plate la, and springs i6 bear against cover 6 and actdirectly against plate la. In Figure 9 the clutch is shown asdisengaged, and in the event that the clutch is installed in a motorvehicle and the transmission is in gear and the engine is acceleratedsuddenly, auxiliary plate 3 3 advances in the manner previouslydescribed and establishes a driving connection between shafts i and 2,thereby taking up any back-lash that may be present in the driven units.Although it is possible, in this form ,4 of clutch, to moderatelyacceleratethe engine to a fairly high speed, and then suddenly releasethe clutch pedal and thereby produce a clunk, the normal tendency is toaccelerate the engine fairly suddenly prior to engaging the clutch, withthe result that plate 34 is actuated and the slack is taken out of thedrive line prior to clutch engagement. Auxiliary plate 34 functions in asimilar manner when the engine is suddenly accelerated with the clutchdisengaged, for the purpose of speeding up the transmission parts priorto shifting it from a higher to a lower gear. When shifting thetransmission from a lower to a higher gear, disengagement of the clutch,through moving plate Ia to the right, produces clean disengagement ofauxiliary plate 34 prov'iding the engine throttle is closed while thedeclutching operation is being effected.

In Figures 10 and 11, I have illustrated a further modified form of theinvention wherein the auxiliary plate is located in the flywheel andcooperates with the outer region of the driven member.

With continued reference to Figures 10 and 11', an auxiliary plate 34ahaving an abutment face 54, an inclined or cam face 55, and a stop'face56, is mounted for limited oscillation in an annular groove 51 formed inflywheel 4B. Prefer- .ably three actuator members 58, having inclinedfaces 59, are secured within groove 51, by means of cap screws 6! or thelike, and are adapted to advance auxiliary plate 34a when the flywheelis accelerated at a predetermined rate.

In Figures 10 and 11 auxiliary plate 34a is shown in its advancedposition in engagement with driven member ii, and it has been moved intothis position through acceleration of flywheel 4 and the resultingcooperation of faces 59 of plate 34a and faces 55 formed on members 58.The plate lb is allowed to move toward the flywheel under the influenceof springs it, either through automatic operation as is the case in thebrought into engagement with member 58, which limits further movement ofthe auxiliary plate. Although in this form of the invention auxiliaryplate 34a does not manifest self-de-energlzing tendencies when theengine driving shaft is accelerated, it is to be understood that byproperly designing members 58, and providing additional cam or inclinedfaces thereon, this function can be accomplished thereby, and the devicewhen so 7 designed is also intended to be embraced by the appendedclaims.

Referring now to Figure 12, I have illustrated the device shown inFigures 10 and 11, slightly redesigned so as to produce actuation ofauxiliary plate 342: when driving shaft l is accelerated or decelerated.a

With continued reference to this figure, auxiliary plate 34b is providedwith inclined faces 62, merging into abutment faces 54, which cooperatewith inclined faces 63 formed on actuator members 58a. I

In this form of the invention, which is particularly adapted though notnecessarily limited for use in manually operable clutches, plate 34b maybe caused to establish a light driving coupling between shafts I and 2whenever shaft I is accelerated or decelerated.

With reference to Figure 13, I have illustrated a further modificationof my invention which primarily differs from that illustrated in Figures1 to 'l in the means employed for actuating the auxiliary plate. In thisform of the invention the auxiliary plate is actuated by the reactionplate.

With continued reference to this figure, auxiliary plate 380 is adaptedto cooperate with seat 33a formed on plate I ma manner similar to thatdescribed in connection .with the previously described forms of myinvention, and

. pins 3511. project towardthe axis of the mechanism and seat in slots31a formed in the flange $5 of an actuating plate 66, which is securedto reaction plate i3 by means of a plurality of rivets 61. If desired,however, pins 35a may cooperate with slots formed in an integrallyformed portion of plate 83.

Pins 35a cooperate with slots 310. so as to cause theauxiliary plate toadvance and engage the driven member when the engine is accelerated,

and are also preferably operable to effect, retraction of the auxiliaryplate when the engine is decelerated or when the automatic'plateretracts when the driven member tends tooverrun the driving member, but,if desired, slots 31c may be of V-shaped configuration so as to actuatethe auxiliary plate when the engine is decelerated as well as when theengine is accelerated, as is effected-by the device illustrated inFigure 12,-

and the appended claims are intended .to embraces my novel mechanismwhen it is adapted to function in this manner. I

In connection with all of the forms of my invention, it is observed thatwhen the auxiliary plate has become engaged with thedriven mem ber asthe result of acceleration of the drivingshaft, the resulting dragcauses the auxiliary plate to undergo a self-energizing action, and asthe pins thereof react against the automatic or reaction plates, thetotal available reactive force is equal to the combined pressure ofsprings] aorane the engine is frequently suddenly accelerated,

means may be introduced into the device to definitely limit themagnitude of the reactive forces. For instance, the auxiliary plateactuating pin slots may be formed in a separate resiliently backedmember, or cam faces may be formed on the auxiliary plate and be adaptedto cooperate with spring pressed plungers utilizing independent springsor a portion of the forces. .of springs l6, and the appended claims areintended to embrace mechanisms of this character. Also, walls 39 ofslots 3'! may be replaced by leaf springs or the like, so as to limitthe reactive forces to the strength of the springs if desired.

The term automatic clutch as employed in the specification and claims isintended to embrace clutches of the type employing vacuum or other poweroperated mechanism, with or without centrifugally responsive means, foreffecting clutch engagement.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the

scope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come within themeaning and range of equivalency of the claims are therefore intended tobe embraced therein;

What is claimed and desired .to be secured by United States LettersPatent isr- 1. In a power transmitting mechanism, a driving element; adriven element; speed responsive -means for establishing a drivingconnection between said elements; and 'means operable to transmit powerbetween said elements independently of the operation of said speedresponsive means, and at speeds below thedriving-connechon-establishingspeed of said speed responsive means, when one of said elements is givenan acceleration of predetermined magnitude.

2. The mechanism specified in claim 1, where'- in said last-named meansis responsive to rotation of said driving element.

3. In power transmitting mechanism, a driving element; a. drivenelement; driving and driven members mounted for engagement anddisengagement and adapted to transmit power between said elements; meansfor causing said members to be brought into frictional engagementwhenone of them attains a predetermined speed; and means responsive toan acceleration of predetermined magnitude of one of said elements fortransmitting power between said elements independently of the operationof said members, said last-named means being operable below saidpredetermined speed.

4. The mechanism described in claim 3, wherein said last mentioned meansis. adapted to transmit power directly between said members.

5. The mechanism specified in claim 3, wherein said last mentioned meansis responsive to the acceleration of'the driving element.

6. The mechanism described in claim 3, wherein said last mentioned meansis responsive to the acceleration of the driving member and is adaptedto transmit power from the driving tothe driven member.

ao'raiie 7. In a power transmitting mechanism, driving and drivenmembers; a primary power trans mitting device for selectively couplingsaid members; a secondary power transmitting device tend toautomatically couple said members when one of them undergoes anacceleration oi prede termined magnitude; and means, operable inresponse to uncoupling operation of said primary power transmittingdevice, for rendering said secondary device inoperative.

8. The mechanism described in claim 7, wherein said primary powertransmitting device supports said secondary power transmitting device,and said devices are adapted to undergo unitary uncoupling movements.

9. In a clutch mechanism, a pressure plate adapted to irictionallycooperate with a driven member; an auxiliary plate operably associatedwith said pressure plate and adapted to undergo relative axial movementwith respect thereto and irictionally cooperate with said driven member;and means forcausing said auxiliary plate to move axially toward saiddriven plate when an acceleration of predetermined magnitude is impartedto said pressure plate, said pressure plate and said auxiliary platebeing disposed on the same side of said driven member, and movable inthe same axial direction when they undergo engaging movement.

10. The device described in claim 9, wherein said plates are adapted tofrictionally engage a driven member, and said pressure plate is adaptedto apply engaging forces to said auxiliary plate when it is engaged withthe driven member.

11. In a clutch mechanism, a pressure plate and an auxiliary platemounted for rotation and for axial movement; a driven member adapted tobe engaged by said plates; means for moving said auxiliary plate intoengagement with said driven member when said pressure plate is ,given anacceleration of predetermined magnitude, said means being operable tocause pressure to build up between said auxiliary plate and said drivenmember substantially in accordance with the magnitude of the torquetransmitted from the auxiliary plate to the driven member.

12. The mechanism described in claim 11, wherein said means is operableto tend to disengage said auxiliary plate from said driven member whenthe driven member tends to overrun with respect to the auxiliary plate.

13. In a clutch, a pressure plate mounted for rotation and having africtional surface disposed substantially normal to its axis ofrotation; an auxiliary .plate operably associated with said pressureplate and having a frictional surfacedisposed substantially in the planeof the frictional surface of said pressure plate under certainpredetermined conditions, and means for causing said auxiliary plate tomove axially of, and project beyond the frictional surface of saidpressure plate when an acceleration of predetermined magnitude isimparted to said 1 pressure p ate. 4

14. The device described in claim 13. wherein said last-named means isalso operable to actutoward and away from a driven member; an auxiliaryplate mounted on said pressure plate and operable to engage said drivenmember independently of said pressure plate, means for causing saidauxiliary plate to project beyond said pressure plate and engage saiddriven member when an acceleration of predetermined magni tude isimparted to said pressure plate; means for causing said pressure plateto engage said driven member; and means for causing said pressure plateto impart engaging movement to said auxiliary plate when it undergoesengaging movement.

17. The device described in claim 16, wherein said last-named meanscomprises an abutment provided on said pressure plate which is operableto engage behind said auxiliary plate when said pressure plate undergoesengaging movement.

18. In a power transmitting mechanism, driving and driven membersmounted for relative rotation, a primary coupling device for couplingsaid members, a secondary coupling device operable to automatically moveinto a projected position with respect to said primary coupling deviceand 'coupling said members when an acceleration of predeterminedmagnitude is imparted to said driving member, said secondary couplingdevice being automatically movable out of projected position when saidprimary coupling device is operated to couple said members.

19. In a power transmitting mechanism, a. driving member and a drivenmember mounted for relative rotation, a clutch embodying frictionalelements for coupling said driving and driven members, means forestablishing a power transmitting connection between said driving anddriven members independently of the operation of said friction clutchwhen an acceleration of predetermined magnitude is imparted to saiddriving member, said last-named means being of comparatively low torquecapacity and being self-operable to augment its power transmittingaction when said driving means tends to operate at speeds in excess oithat of said driven means.

20. In a power transmitting device, driving and driven means; frictionclutch means for coupling said driving and driven means, a secondfriction

